Sterilized apple moth program starts this summer

(March 31, 11:45 a.m.) The U.S. Department of Agriculture and the California Department of Food and Agriculture are preparing to launch a major assault on the light brown apple moth, a pest that could devastate many of California’s fresh produce crops.

The weapon of choice is millions of sterile male moths.

“We’ll probably start releasing the moths in early summer,” said Larry Hawkins, a Sacramento-based spokesman for the USDA’s Animal and Plant Health Inspection Service. “We’ll start small in rural areas where we have easy access to traps and can put the traps at uniform intervals.”

By starting small, researchers will get an idea how the insects distribute themselves, how healthy they are and how long they live, Hawkins said. Those findings determine how many sterile moths need to be released per square mile.

The moth, discovered two years ago in Berkeley, has spread to at least ten counties in the San Francisco Bay area. Some of the moths were trapped within a few miles of the vegetable rich Salinas Valley, but have not yet been found in the state’s other major growing regions.

The federal-state task force that is coordinating the effort has moved from portable offices at the Santa Cruz County fairgrounds to a larger building in Moss Landing, Hawkins said.

“The new building allows us to locate all of the regulatory and trapping staff and administrators in one building and still have room enough for insect rearing,” he said.

Part of the colony of apple moths from the Albany, Calif., office of the USDA’s Agricultural Research Service has been transferred to the Moss Landing facility. When fully up to speed, the Moss Landing facility will produce millions of moths weekly. As the males mature, they will be taken first to nearby Lawrence Livermore National Laboratory to be sterilized by irradiation, Hawkins said.

“It’s the same type of procedure we’ve used in the past to eliminate Mediterranean fruit fly and Mexican fruit fly infestations in California,” he said.

Controversy Still Swirls

Not all scientists are convinced the sterile moth program will eradicate the pest.

“This idea that you can get rid of the moth that has spread from Monterey County all the way to Sonoma County and every place in between is just nuts,” said James Carey, a professor of entomology at the University of California-Davis. “There’s zero chance.”

A hurdle that is impossible to overcome, he said, is the wide range of hosts — more than 200 plants — for the apple moth. Carey estimates there may be one million homes in the region infested by the moth and that each home may have an average of ten host plants or shrubs.

“If the eradication program misses just a couple of the pests on someone’s patio, the problem starts all over again,” he said. “In five years you’re going to be $75 million poorer and be in the same place you are right now.”

Hawkins countered that the USDA and state agencies have proved in several states including Texas, Florida and California that the sterilization program has worked for other pests.

“We’re been doing it successfully for Medfly and the Mexican fruit fly infestations since back in the late 1980s in California and for the pink bollworm, too,” he said. “Now we’re adapting the technology for the light brown apple moth.”

The moth, a native of Australia, had never before been found and identified in North America until its discovery in 2007. But scientists do not believe the sterilization technology will require major modifications, because they believe the pest is similar in behavior to the pink bollworm, Hawkins said.

A better and more cost-efficient approach, Carey said, would be to control the infestation by using pheromone-laced twist-ties, pheromone sprays and sterile moths to create certified pest free-zones. The zones would be certified pest free if no moths were trapped over a specific period.

“It’s called area-wide management, and it’s a different concept directed toward quarantine pests,” he said.

That the apple moth could migrate to the tens of thousands of acres of cropland in the San Joaquin Valley, which at its closest point is about 60 miles from the infestation — is not a concern, Carey said.

“It’s too hot in the valley for the moth to survive,” he said.

If Carey’s opinion proves to be wrong, the effect on California produce could be devastating. A USDA study concluded that if the moth infested growing regions of California, annual crop losses would exceed several hundred million dollars.